Alexander mclennan



UNITED STATES Q T F IC ALEXANDER. MCLENNA'N, or Lorin-on, EnGLanDQ TREATMENT OF LEATHER WITH INDIA-RUBBER.

80 Drawing.

speciflcation ot Letters Patent. Application filed SeptemberiB, 1909. Serial No. 519,981.

In carrying the inventioh into eifet the leather is first subjected to any well known fat liquoring process which has the eifect of not only softening it so that it can be more conveniently handled or worked, butat the same time should the leather be dry causes the pores of the leather, which have. contracted to expand. The hides after the llquormg treatment are secured to the dry ing frames from. which they are removed' whendry and buifed upon the flesh side in order to raise the fiber. treatment the hides are, treated with a so lution, designed to kill the fats or oils in the leather and hereinafter'referred to as a. clarifying solution, in which they may be immersed, or which solution may he s rayed or otherwise applied to them, and a tor the application of the solution they are laced in a hermetically closed vessel in whic they remain for a suitable period according to the weight and character of the hide, which period with hides of average weight will be about 48 hours. The clarifying solution to which the hide is first subjected may be composed of thefollowin ingralients in about the proportions specific modified to suit the quantity or character of'the hides. The proportions 'venbelow are however such as I have foun to be suit-- able for .lchrome tanned hides of average weight and would be suflicient in quantity to treat from to of such hides :'powdered sulfur, 1 1b., carbon bisulfid 4 lbs. The mixture is allowed to stand for a period of 48 hours with occasional agitation, at the end of which period it is strained, and to the liquid residue is added a second mixture found verysuitable for this pur ose, but I do not confine myself to its use.v ulfuric ether 5 12 oz., benzol 10 oz. to 12 02., coal tar naphtha After the latter 7 a d, the'said pro- I portions and lngredi'ents howeverbeing 10 oz., petroleum benzin 6 oz.,kerosene 4 Patentease a- '20, 1910.

oz., rectifiexl spirit of turpentine 4 oz. These j quantities are those. suitable for addition to 5 lbs. of the carbon bi-sulfid solution for the treatment of average hides.- \Vhen lighter hides such as rabbit skins are being treated I may omit the kerosene and turpentine. Two or three ints oftheabove combined mixture is ta en and to it is added 5' gallons of benzin the liquid thus 'formed being employed to treat the hides in, the

manner before stated. As it isadvisable that only the smallest particles of sulfur be held in suspension in the" liquid so that the pores of the hide shall not become choked up, the liquid may be again subjected to the straining operation. After this treatment the hides are removed and dried by heat,

and when dry and while still warm are treated with a solution containing rubber.-

'While the-preparation of the aforesaid rubber solutions may be effected in any convenient manner I findinpractice that it is convenient to prepare a stock-solution of the rubber which may be prepared by dissolving 1 lb. of Para rubber m from 1 gal. to 2 or more gals. of naphtha according to the condition or purity of the rubber. Obviously.'other rubber than Para rubber may be employed but when such other rubber isused'it ay-be'necessary to increase either the proportion of the rubber or of the naphtha. Instead of naphtha any other suitable rubber solvent may be used, such -for example as carbon bisulfid or benzol. In preparing'the first bath from the stock solution I ordinaril take "equal parts of the rubber solution an benzin, the hide being treated therewith as aforesaid; the roportions I of the rubber'and benzin wil however, depend upon the condition of the stook a solution.- v

The hides while in the rubber solution are heated and with this object the vessel may be jacketed so that steam, water, or .other meansmay be employed and the temperature of the said'vesse' perature may range from 80 to Fahr.

and the period of treatment may extend from 2 to 5 days in each bath. .It will, however, be evident that the weight, natureand origin of the hides must in all cases be considered and the treatment modified accord' y- The hides during the foregoing treatment regulated. The temmay be mechanically agitated, or the hides.

should be removed fromthat to time an worked by hand, or the liquor in the vw'sel kept moving in the vessel or any other means'employed so that the hand working ma be'dispensed with.

heleather is next subjected to a second treatment with rubber, in combination with a sulfur solution. The second rubber solution should be of a somewhat more viscld nature, that is to say, it should contain a greater quantity of rubber. For the second ath I again dissolve one part of powdered sulfur in about four parts of carbon blsulfid and allow it to stand as before. To this there is again added a mixture adapted to precipitate the undissolved sulfur and there is further added chlorid of sulfur. The fol:

lowin gives what I have found to "be a very suitab e mixture. 1 part powdered sulfur dissolved in 4 parts carbon, bisulfid 5.lbs.i

sulfuric ether 12 0a., benzol 10-12 92., cos.

tar na htha' 10-oz., petroleum benzin 6 oz.,

chlori of sulfur 10 oz. About 1% gallons of this are added to every 50 gallons of a rubber solution which should contain more rubber than the first bath, a 'suitablecomposition of such "rubber solution bein 4 parts,

of benzin-to 5 parts of the stock ru her solution.

I ma more 0 the above specifi in this ,case the quantity the remaining precipitant or precipitants would be pro-'- portionatel -varied. I find however as aforesaid that the above combination gives the best results.

in some cases dis cnse with-one or After the treatment last referred to the hide is drummed or otherwise mechanically treated with a final rubber-solution in order to stuff the hide and according to the weight of the hide the stufling'process occupies from 12 to 24 hours.

In the case of the final drummin ,1 or other treatment as aforesaid, I emp 0y 8. rubber solutioircomposed of 1v part stock solution to 2garts benzin, and to every 10 gallons. of sai rubber soiution I add 4 ints of the chlorid of sulfur solutioujust a ove described. aforesaid, however, the

quantitiesjof the various ingredients, may

be altered as may befound necessary to suit the particular re uirements of each case so far as the finish roduct is concerned and having regard to e weight and character of the hides being treated. The hides when taken away from the drum should be placedupon a suitable surface and slicked or scra edto remove the surface rubber, the

sur us rubber .bein finally removed by rub in with a cloth 'pped 1n benzin. The

hide a er the removal of surplus rubber is hung-up and when partly dry is rolled coinpletlng the treatment.

precipitants but 0 Having now particularly described and ascitained the nature of my said. invention,

and in what manner the sameis to be per formed, I declare that what I claim is 1. A process for the treatment of tanned leather consisting in treatin the softened and dried leather with a clarifying solution containing powdered sulfur dissolved in carbon, bisulfid, of: which,

.after standing, 'is added a mixture adapted to precipitate any' undissolved's'ulfur and dissolve .any fats; then after treating them with a heated solution containing indiarubber dissolved in a suitable solvent, the hides being worked during the treatment; afterward subjecting toa second heated bath also containing rubber in solution together with a to the liquid, residuesolution of powdered sulfur, carbon bisulfid,

chlorid of sulfur together. withsulfur "pres cipitating substances, the hides being worked during the treatment; and finally drummingor agitating the hides-in a'third solution containingrubber in solution together with.

powdered sulfur, carbon bisulfid, cl1lorid of sulfur and sulfur precipitating substances ;j

the" surplus; rubber adhering to thehide being then slickered ofi and; the hide finished with a cloth dippedin a rubber solvent; the" treatment being finally completed 'by rolling the partially dried hide."

2. A process for the treatment of tanned leather consisting in tree the softened and dried leather with-a clarifying solution containingsufiiwderedsulfur dissolved in carbon b1 d, to the liquid res'idu'eof which, after straining, is added sulfuric ether, benzol, naphtha benzin, kerosene, rectified spirit of turpentine; then' after drying, treating them in 'a sealed vessel with a heated solution containing india-rubb'er in a suitable solvent, the hides being worked during the treatment; afterward subjecting to a second heated bath also containing rubher; in solution together with. a solution of powdered sulfur, carbon -bisulfid, chlorid' of sulfur together with sulfur precipitatingsubstances," the) hides bein a in work ,during the treatment; and i y drumming 'or agitating) the hides ina third solution containing ruber in summon together with powdered sulfur, carbon bisulfid, chlorid of sulfur and sulfur preci itating substanoes;-' the surplus rubber a ering' to the hide being then slickered off and the hidefinally finished with a cloth dipped in a rubber solvent; the treatment being finally finished by rolling the partially dried hide.

' 3. process for the treatmentoftanned leather consisting in treating the softened. and dried leather with a clarifying solution containings'uigwdered sulfur dissolved incarbon bi d, to the liquid-residue of which, after strainin is added sulfuric.

ether, benzol, naphtha, nzin, kerosene, rectified spiritof turpentine; then after drying,

treating them in a sealed vessel with a heated rubber solution; the hides being worked during the treatment; afterward in a sealed vessel with a heated solution containing india-rubber in a solvent, together with powdered sulfur and bisulfid of carbon, to the liquid residue of which, is added, sulfuric ether, ben zol, naphtha, benzin and chlorid of sulfur, the hides being again worked during the treatmentg a'nd finally being drummed or" agitated in a solution containing india-rubber in a suitable solvent together with carbon bisulfid and a chlorid of sulfur solution containing sulfur precipitating substances; the surplus rubber adhering. to the hide being then slickered off and the hide finished with'a cloth dipped in a rubber solvent; the treatment being finally completed by rolling the partially dried containing powdered sulfur dissolved in carbon 'bisulfid, to the liquid residue of which, after straining, is added sulfuric ether, benzol, naphtha, benzin, kerosene, rectified spirit of turpentine; then after drying, treating them in a Sealed vessel with a heated rubber solution the hides being workediduring the treatment; then treating them in a sealed vessel with a heated" s0-v lution containing india-rubber in a solvent,

being worked during the treatment and finally being treated with agitation in a solution containing india-rubber in a solvent,

powdered sulfur and carbon bisulfid, vthe liquid residue of which after straining having added to it, sulfuric ether, benzol, naphtha, benzin, and chlorid of sulfur; the surplus rubber adhering to the hide being then slickered off and the hide finished with a cloth dipped in a rubber solvent; the treat- 'ment being finally completed by rolling the partially dried hide. Y

ALEXANDER MCLENNAN. Witnesses 4 JoHN'H. JACK, REGINALD T. GODFREY. 

